348 GLANDULAE HAIRS, Chap. XV. 



difference from the glands of other hairs. Perhaps there may 

 not have been time enough for absorption. I think so as some 

 glands, on which dead flies had evidently long lain, were of a 

 pale dirty purple colour or even almost colourless, and the 

 granular matter within them presented an unusual and some- 

 what peculiar appearance. That these glands had absorbed 

 animal matter from the flies, probably by exosmose into the 

 viscid secretion, we may infer, not only from their changed 

 colour, but because, when placed in a solution of carbonate of 

 ammonia, some of the cells in their pedicels become filled with 

 granular matter ; whereas the cells of other hairs, which had 

 not caught flies, after being treated with the same solution for 

 the same length of time, contained only a small quantity 

 of granular matter. But more evidence is necessary before we 

 fully admit that the glands of this saxifrage can absorb, even 

 with ample time allowed, animal matter from the minute 

 insects which they occasionally and accidentally captm-e. 



Saxifraga rotundifolia (?). — The hairs on the flower-stems of 

 this species are longer than those just described, and bear pale 

 brown glands. Many were examined, and the cells of the 

 pedicels were quite transparent. A bent stem was immersed 

 for 30 m. in a solution of one part of carbonate of ammonia to 

 109 of water, and two or three of the uppermost cells in the 

 pedicels now contained granular or aggregated matter; the 

 glands having become of a bright yellowish-green. The glands 

 of this species therefore absorb the carbonate much more 

 quickly than do those of Saxifraga umbrosa, and the upper 

 cells of the pedicels are likewise affected much more quickly. 

 Pieces of the stem were cut off and immersed in the same 

 solution ; and now the process of aggregation travelled up the 

 hairs in a reversed direction; the cells close to the cut sur- 

 faces being first affected. 



Primula sinensis. — The flower-stems, the upi^er and lower sur- 

 faces of the leaves and their footstalks, are all clothed with a 

 multitude of longer and shorter hairs. The pedicels of the 

 longer hairs are divided by transverse partitions into eight or 

 nine cells. The enlarged terminal cell is globular, forming a 

 gland which secretes a variable amount of thick, slightly viscid, 

 not acid, brownish-yellow matter. 



A piece of a young flower-stem was first immersed in distilled 

 water for 2 hrs. 30 m., and the glandular hairs were not at all 

 affected. Another piece, bearing twenty-five short and nine 

 long hairs, was carefully examined. The glands of the latter 

 contained no solid or semi-solid matter ; and those of only two 



